An angler's release of a record largemouth bass from a Bay Area lake is part of a national effort to let the big ones go at lakes and streams.

The record fish weighed 18.02 pounds, a record at Contra Loma Reservoir in the foothills of Antioch.

Craig Avery, who caught the fish on Easter, said he used a nightcrawler for bait at a spot called Channel Point. After the fish was measured and photographed, it was released.

It was one of the largest bass in Bay Area history, less than a pound smaller than the Bay Area record (18 pounds, 11.2 ounces, caught at San Pablo Reservoir).

Bass and trout can live up to 15 years; sturgeon as long as 70 years. Because of that, many enlightened anglers are choosing to release the big ones. It gives the fish a chance to become even larger, and in the process, pass along its genetics to its progeny.

In other words, why kill the very thing you find so desirable?

A good friend of mine, Hal Janssen, caught and released a lake-record 24-pound brown trout at Lake Almanor, the same fish I believe I fought and lost at the boat (at the same spot, too). We estimated the fish was 15 to 20 years old.

In a stream, only 5 percent of wild trout survive the first year. For the few that survive, it often takes five or six years for them to reach 12 inches With some luck (50 percent mortality each year), they can live 10 to 15 years.

That's why rivers where anglers keep the big ones and throw back the small ones, like the Stanislaus, end up full of dink-size trout.

If you want to catch a fish to eat, a better bet is to keep a hatchery-bred trout that has become naturalized in a lake, a salmon, halibut or lingcod from the ocean that gets big in just four years, or a school-fish that grows fast, like crappie in lake, blue rockfish from the ocean, or a 12- to 14-inch bass from a reservoir with high water quality.

Sightings

Chabot nest: Bald eagles have hatched two chicks at a nest in a eucalyptus grove at Anthony Chabot Regional Park in Castro Valley, reports biologist Doug Bell. You can watch the action with binoculars or a spotting scope from the West Shore Trail, where you scan across the lake to the trees on the peninsula between Half Moon Cove and Bass Cove.

Fairfield eagle: A bald eagle was sighted at Rockville Hills Park in Green Valley near Fairfield, unheard of for the area. The bird sailed overhead just 100 feet high and caused a jaw-dropping sight for several locals, reported David Schajatovic.

Good, bad, good: At Mare Island, John Golding watched two ospreys build a nest on the pulley of a crane, halfway up the boom. The crane operator later started up the rig and blew up the nest. The story might have a better ending: Last week, Golding sighted the birds building a nest a few hundred yards away.

Catches

Wayward fish: A rare fish called a Buffalo sculpin - which looks like a bullhead with long, sharp barbs from each gill cover - was caught last week at Pillar Point Reef in Half Moon Bay. These small fish more common in Washington and Oregon, are very rare on the Bay Area coast. The angler who reported it, Norm Sleep, had the awareness to take a photo before letting it go.

Live bait: With striped bass migrating into San Francisco Bay from the delta and halibut from the ocean, live anchovies will be available for bait at Pier 45 in San Francisco, 6 a.m. to 9 a.m., and the potluck season is a go, reported Capt. Robert Gallia of the El Dorado.

Outdoor notes

Record find: In Cadomin, Alberta, the skull and horns of a huge bighorn sheep that died of natural causes was found by wildlife officials, and the preliminary scoring would make it a world record. It has been submitted to Boone & Crockett for formal review.

NorCal condors: California condors, which haven't lived north of the Big Sur area since the 1800s, would be released in the Redwood Empire in a new captive-breeding test program run by the Yurok Indian Tribe, approved in April by federal wildlife officials.

Monterey update: Massive patches of krill arrived in Monterey Bay last week, adding to the rich food production already supported by huge schools of anchovies, reported Capt. Michael Sack of Sanctuary Cruises. Humpback whales then arrived in large numbers at midweek, along with the first blue whales of the season.

Ocean Beach: The past few weeks have been good for whale watching at San Francisco's Ocean Beach, and Diane Stammerjohn was on site April 25 when 15 whales, with several calves, roamed a few hundred yards offshore. They then put on a big show offshore at the foot of Balboa Avenue.

Sierra crossings: In case you missed my tweets, 9,943-foot Tioga Pass (Highway 120) in Yosemite, 9,623-foot Sonora Pass (108) and 8,730-foot Ebbetts Pass (4) are open for the season for Sierra crossings.

Tahoe boat inspections: Roadside boat inspections, required before launching a boat at Lake Tahoe, again do not open this summer until 8:30 a.m. each day, even though the best fishing is from dawn to 7:30 a.m. Fees also remain the most expensive anywhere, a $55 gouge job for an 18-foot fishing boat for a "Tahoe In and Out" sticker, good for a week.

Q&A: "Does a kayak need to be registered in California? Can you put a kayak in Lake Merced?" - Cliff Serveti. A: Kayaks and canoes do not need to be registered as long as they do not have a motor on them; at Lake Merced, kayaks, canoes, sculls and fishing boats (no gas engines) are permitted.